Buckle for a safety belt



A ril 13, 1965 R. H. SVENSSON 3,177,545

v BUCKLE FOR A SAFETY BELT Filed April 3, 1962 2 Sheets-Sheet 1 INVENTOR$1 Han n'!( .J ve n Json April 13, 1965 R. H. SVENSSON 3,177,545

BUCKLE FOR A SAFETY BELT Filed April 3, 1962 2 Sheets-Sheet 2 INVENTOR10H l/um'x Jrcnssan ORNEY United States Patent 3,177,545 BUCKLE FOR ASAFETY BELT Rolf Henrik Svensson, 1 Viktoriagatan, Halmstad, SwedenFiled Apr. 3, 1962, Scr. No. 184,775 Claims priority,applicagtgznsslweden, Apr. 17, 1961,

3 1 Claim. (Cl. 24-170) This invention relates to buckles for safetybelts and similar strap members.

More particularly this invention relates to safety belt buckles and thelike elements having a base portion for securing one belt-part, a flapactuated by a spring member and an internal locking member actuated by asecond spring member, said locking member having a portion, suitablyknurled or serrated, for clamping against the other belt-part, saidlocking member further being adapted, upon-release, to be pivoted out ofits locking position by the flap.

Buckle constructions known in the prior art have generally the drawbackthat the flap, in order to provide satisfactory locking of the otherbelt-part, will project with its free end from the base portion or fromthe two superposed belt-parts, with the result that the flap becomes aprotrusion and may be opened accidentally.

One main object of the present invention is to eliminate saidinconvenience so that the free end of the flap conforms to thebelt-parts.

Further objects and advantages of the invention will become apparentfrom the following description, considered in connection with theaccompanying drawings which form part of this specification and ofwhich:

FIG. 1 is a sectional view along line II of FIG. 3 of a buckleconstructed in accordance with the invention.

FIG. 2 is a perspective view of the buckle shown in FIG. 1 and with someportions of the buckle and the belt assumed removed for clarity. FIG. 3is a plan view of the buckle shown in FIGS. 1 and 2.

FIG. 4 is a sectional view along line IVIV of FIG. 5 of anotherembodiment of a buckle according to the invention. FIG. 5 is a plan viewof this buckle.

FIG. 6 is a perspective view of the buckle shown in FIGS. 4 and 5. Inorder to obtain improved clarity, some parts are supposed removed inFIGS. 5 and 6.

In both embodiments illustrated by FIGS. 1 to 3 and 4 to 6,respectively, certain of the same reference numerals have been employedto denote equivalent parts; some of the numerals and others of thenumerals followed by primes denoting parts of forms difliering from theforms of certain corresponding parts denoted by unprimed referencenumerals.

Referring to he drawings and in particular FIGS. 1 to 3 a base portionof the buckle is denoted generally by It) and has a substantiallyU-shaped cross section with marginal flanges 12. The base portion may bemade of sheet plate and has a cross-slit 14 through which the endportion 18 of one belt-part 16 is threaded to then be looped and unitedwith the underlaying portion of the belt. The marginal flanges 12 areprovided with apertures for a cross-pin or shaft 20 secured againstrotation in relation to the base portion 10, for instance, by the pinhaving a hexagonal head 22 entering into a complementary recess in onemarginal flange 12. Pivotally mounted on the pin 20 is a flap 24 whichlikewise may be made of sheet plate, said flap having marginal flanges26 through which the pin 20 passes. A spring member 28 is disposedaround pin 20 and has one end secured to said pin and extending at itsopposite end through a hole 29 in the flap 24. The

spring member 28 urges the bent handle end 34 of the flap 24counter-clockwise, as viewed in FIG. 1, against the base portion 10.

A locking member 32 is rotatably mounted inside the flap 24 on the samepin 20 as the flap; said locking member is, however, capable ofperforming a limited angular movement in relation to the flap. Thelocking member is actuated by a spring member 34, the end portions ofwhich are rigidly secured to the locking member and the pin 20,respectively. The locking member is provided with a knurled or serratedportion 36 for clamping the other belt-part 38 against the base portion10, which may have for this purpose a backing section in the form of aprotuberance 40.

The locking member 32 has a recess 42 through which the spring member 34is inserted at the assembly before the pin 20 is pushed through thelocking member. The pin may have a longitudinal groove 44 for receivingthe one end portions of the two spring members 28 and 34. The recess 42may be closed afterwards. The spring member 34 tends to rotate thelocking member 32 in the same direction as the flap 24, the freedom ofmovement of the locking member being limited, however, by a shoulder 46.Either one or both spring members may be pre-tensioned. Inside the flapthe locking member 32 is extended into a tongue 48 or similarprolongation which serves for preventing the locking member fromaccidental rotating in relationship to the flap 24, as will be explainedin greater detail below.

The buckle is primarily intended for use with safety belts for seats invehicles, such as airplanes and cars, and it operates in the followingway.

When the flap 24 is put up so that its handle-end 3i 1 leaves the baseportion 10, the locking member 32 after some angular movement of theflap is brought along by virtue of the shoulder 46 on said member. Bothspring members 28, 34 are then cocked. At the same time the lockingmembr 32 has withdrawn so far from the protuberance 40 of the baseportion that the belt-part 38 may be introduced between the twoelements. After a proper tightening of this belt-part the flap 24 isreleased, whereupon it returns to a position in which its handle-end 3tbears against the two superposed belt-parts. The locking member 32 doesnot accompany the flap throughout its entire angular movement but stopsearlier so as to bring about the proper locking effect against thebeltpart 38. In other words, the flap 24 moves slightly further in acounterclockwise direction as viewed in FIG. 1 relative to the tongueportion 48 of the locking member. The angular displacement required inorder that the beltpart 38 be retained in its tightened position is thusimparted to the locking member 32 and not to the flap 24.

It will readily be understood that the locking member 32 cannot (theshoulder 46 being disregarded) rotate counter-clockwise, as viewed inFIG. 1, in relation to the flap 24 further than to a position whereinthe tongue 48 clamps the belt-part 38 against the lower portion 1% Thislimitation of the freedom of movement has for its object to preventfailure of the locking member in cases of catastrophy and the like, whenthe safety belt is subjected to a very large, more or less momentaryload. The stress on the buckle would then be so large that the flap 24could give and release the shoulder 46 of the locking member so that themember could rotate counterclockwise in relation to the flap, as viewedin FIG. 1. However, the tongue 48 limits this rotation so as to ensurethat the knurled portion 36 would still be effective, at leastpartially, to maintain the belt-part 38 locked.

In the embodiment shown in FIGS. 4 to 6 the locking I member 32' has aknurled portion 36', and a tongue portion 48 for limiting the clockwiserotation of member 32' as shown in FIG. 4. Member 32' is formed with acentral recss 50 housing a spring member generally denoted by 52 anddrawn around the pin or shaft 20. This spring a spring memb'erarepre-tensioned;

1 The pin'20 is kept locked relative the-'basepart 10 by manner as inthe embodiment shown in'the FIGS. 1' to 3" the pin 20 has a longitudinalgroove '44' into which a por tion 60 (FIG; 4) of the springmemb'erjSZ isintroduced and therewith immobilized relative said pin. Between saidportion 60 and the end portion 58 the spring member is disposed inagroup of windingsfilaround the'shaft-actu ating the locking member 32"and is thus-tensionedwhen said locking member is moved upwards. Anothergroup 64 of windings of the spring member'formed between the j endportion 5 4 and the portion 60 is adapted tolactuate the flap 24.-Preferably both groups of windings of the means of alpi'n 66. In theaxial direction the shaft is blocked by means of retaining rings 68;While several more or less specific embodiments of and the locking theinvention havebeen shown and described,'itisto. be

understood that this is for purpose" of illustration only; and that theinvention is not to be limited thereby, but;

its scope is to be determined by the appendedxcla-im. What I claim-is: aV A safety belt buckle comprising V: (a) a base to which one end of abelt'is adapted to be secured, a j (b) a flap mounted at one end onsai'd'base to pivot between an open anda closed position, respectively,-(c) a first spring uprging said flap to its closed position,

(d) a locking member mounted within said flap be-' tween said flap andsaid base for'oscillation about the pivotalaxis of said flap between alocking posi-- tion and a released position, respectively,

formed to clamp the other end of a belt against said v base, when saidmember is'in' itslocking position, I '(f) 'a second spring urging saidlocking member towards its locking position independently .of said firstspring and of said flap but in the same direction as the first-namedspring urges said flap, and (g) a shoulder-formed on said lockingmemberand projecting through'a slot in said' fla'p to beengag'ed by said'flaptci pivot said locking'member from its locking position toits'released'positiofij whens'aid flap is moved from its closedl'to itsopen position, (h) said slot extending about said pivotal axis adistance sufiicient to'disengagesaid shoulderupon'movement of saidlocking member and said flap, under .the:

action of said springs, to saidilocking positionand'to said closedposition, respectively, whereby said flap must move independently ofsaid locking" member towardttheopen position of saidflap beforemovingsaid lockingmember' toward released position, and:

References Cited in the tile of this patent I UNITED STATES PATENTS:

2,517,424" Griswold-;. Aug. 1,1950" 7 2,867,876 Elsner et a1. Jan. 13,1959 2,869,200 Phillips et a1. Jan. 20,1959. 2,916,786 Legat Dec; 15,1959' 2,965,942" Carter V-V Dec. 27,1960 1 Y OTHER-REFERENCES" V a1,204,470 7 'France W Aug-10," i959

